Simplifying with Complexity

Sometimes the quickest and easiest way to solve an easier problem isn’t the best way to approach a hard problem. Today (first day of course content in my Pre-Calculus class) we were reviewing sets of numbers, categories of numbers, and notation. I gave my class the following set:

{-2, -1, 0, 1, 2, 3}

and asked them to turn it into set builder notation. Every student was able to write the set as some variant of the following:

Set Builder AV

I asked if there were other ways of writing it, and some people changed the set of integers to whole numbers or natural numbers, but that was about it.

Then I asked the class to do the same thing with the following set:

{3, 6, 9, 12 … }

And they struggled, and struggled. I saw a lot of students just going nowhere. As they worked, I went back to that original set, and wrote up a more complicated solution:

Set Builder EW

One student looked up, then another. A couple of students started working out how my solution worked. A couple of others asked for clarification. And then, one by one, I started to hear those magical “Ohhh!” sounds that we all love – you know that light bulb moment. Students started to remember that they could match each term to a number, and most of them came up with something like this:

Set Builder RBFrom a desk off to the side, I heard a student exclaim, “Whoah! When you showed us a more complicated way to do the easy problem, it made it easy to do the hard problems!”



Day 1 Debate – What’s the Best Number?

I know that by now, most schools have started. I think I’m one of the last that still starts after Labor Day – not that I’m complaining. A popular blog post out there is a first day activity, and I wanted to share the one that I’ve done the past few years. Yes, it’s a debate, but a totally informal debate, one that works at any level of mathematical background, students have a lot of fun with, that builds both competition and teamwork in a low stress way, and tells me a surprising amount about my students.

After normal introductions, I give students a simple task – to come up with a number. It could be a favorite number, or a really interesting number, or a number that has some personal meaning. I then ask them, once they’ve decided on a number, to come up with as many interesting things about that number as they can, and give them a couple of minutes. They can use calculators, they can use the Internet, they can draw, and if they get stuck they can ask me for help (though, to be honest, they rarely ask for help with this).

After a few minutes, when at least some of the students are feeling like they’re done, I have them get into pairs, and then in the pair they decide which number is better. They are given about one minute to make their cases and decide, and once each pair has decided, I have each pair find another pair, and decide which of the two numbers is better. It’s interesting to me that I never actually describe this to students as a debate, and in theory they are working together, but they do have something invested in the number that they came with. Inevitably, groups start to argue, but generally nicely, and the whole idea of comparing the best and worst qualities of numbers becomes a source of passion.

The process of finding another group and then discussing, then finding another group and discussing, continues until you have (hopefully) two halves of the class shouting at each other about whether 32 is a better number than 360 (because powers of 2 are more important than having lots of factors and describing the degrees of a circle), or whether 12 is better than 18 (but of course 12 is better). bradymanning

In listening to conversations that happen, I can get to know an amazing amount about student interests, as well as which students feel very comfortable with what numbers mean and how they can be manipulated and described mathematically. On top of it all, having an entire class passionately engaged in a meaningless debate about which number is best, where you can catch every student having fun playing with math from day one, is a pretty great way to start the year in my opinion.

So, what’s your favorite number? Why?

Seeking My Role in Diversity in HS Math Classes

I want to be clear. I teach in a private high school in Silicon Valley. Many* of the students at my school are white and come from wealthy families. Most of them have gone to either very good public schools or very good private schools, where most students received a generally good education in mathematics. It may not have been perfect, and our students may have slipped through the cracks, or been told that they weren’t math people, or somehow may have received the message that higher math wasn’t going to be for them. Yet those students were still exposed to the important ideas that they were expected to see, from fractions through basic algebra, from area formulas through linear equations and graphs. When that group of students has “Algebra 1” on their transcript, and they received a B in the class, we have no reservations about putting them into a Geometry class.

Our school also has a large number of students of color, and many* of our black and brown students came from very different schools. While most of Silicon Valley is quite expensive, there are pockets and neighborhoods up and down the peninsula that are considered low income areas. In some of these neighborhoods’ schools, some of our students receive a very different math education. I have seen students who received an A in an Algebra 1 class who had never seen a parabola, who had never factored a trinomial, and who were not consistently able to solve a single variable linear equation. In most cases, this was no fault of their own, and it is not my place to fault their Algebra 1 teacher.

These two different experiences are not an accident. Make no mistake about it, this is systematic racism. As Morgan Fierst posted in a conversation on twitter:

She is absolutely right. But what to do about it? The obvious answer is to dismantle the system, but how does that happen? There is definite harm happening in some elementary and middle schools that serve primarily students of color, but one thing that has become clear to me is that, as a white male high school teacher, I have no right to go in and tell other teachers, especially K-8 teachers of color, how to do their job better. My role is to find the leaders among K-8 teachers and teacher leaders of color and support them, and back them up, and give them my power to dismantle the system.

And what about my school? One of the deciding factors in me taking a job at my school was the high retention and low turnover rate. In my four years, we have had a science teacher retire (and then pass away), an art teacher go to graduate school, and a sign language teacher decide to become a stay at home mom. We have hired three outstanding replacements for those teachers, but only one was a person of color. One third of new faculty hires being non-white is an impressive number if we were hiring 200 people or 40 people, but not when hiring only three. I am not in charge of hiring, and I don’t know how much of an emphasis was made on looking for non-white teachers to interview. We are a small school and don’t have a lot of resources for hiring, and we are not a target school for lots of graduates of teacher credential programs. Maybe we couldn’t have done any better.

Our Head of School retired this past year, and there was an exhaustive search for just the right candidate. Our search committee decided on three very competent finalists, and again, one out of those three was a person of color. My question to each of those candidates was the same: “Our school prides itself on the diversity of our student body, but our faculty doesn’t look the same. We have an amazing and talented group of teachers, but we are mostly very white. Without firing faculty members, how would you improve the diversity of our teachers and staff?” It was an unfair question, and one without an obvious answer, but it was also a question where it was clear which one of the members had given it a lot of thought long before I had asked about it. No surprise, it was Phil Gutierrez, the one candidate who hadn’t lived with white privilege, and I am very happy that he is now on board as our new Head of School. I don’t think he has the answer (because, really, does anyone have the answer yet?), but I do feel that he has the same goal in mind.

For me, in my closed world of math education, the goal is to make sure that the higher level math classes have the same diversity as our general student population, and that our students who choose STEM careers in more rigorous schools are a diverse group of students. However, the end result of those students who enter 9th grade not prepared for  success in Algebra 1 or Geometry (despite what their transcript may say) is that they don’t take higher math or attend rigorous schools or choose STEM careers at the same rate as their white peers. They end up either taking a Pre-Algebra class and end up “behind”, or they struggle to keep up in their Algebra 1 or Geometry class, doing lots of extra work and getting extra help to catch up to their peers on the fly. The extra work and extra help takes extra energy and time that they frankly shouldn’t have to put in. Yet, what options do they have? What options do I have? And what options does our school have?

Over the past few days, I have read and followed and participated in several Twitter threads about these questions of equity and diversity. One blog post by Matt Vaudrey could have been written by me (if I was a better writer, and maybe got a few more squares in privilege bingo). Two new people I found to follow on Twitter, Twila Dang and Morgan Fierst, pushed me hard to think more about the systemic racism that exists, and made me wonder where I and my school still have work to do. Because the fact is that the moment a student becomes my student, their background, their previous experiences, every math class that they’ve experienced in the past is a real part of them, but it cannot be an excuse for why I can’t help them to be the best mathematician that they can be during the time I get to spend with them. As I write this, I realize that I’ve taken great care to focus on students with disabilities and non-male students, to help these traditionally disenfranchised groups see their potential and embrace their abilities in mathematics. I am proud of the work I’ve done in this area, and receive a lot of positive feedback and accolades. I have to wonder, though, why I haven’t made the same concerted effort with students of color. After 16 years of teaching, it’s a difficult realization, but one that I’m glad I finally made. Maybe this is the catalyst for the next phase of my teaching career. I think I have more clarity on my goal for year 17 and beyond, but I welcome any suggestions and feedback.

*To be clear, there is a diversity of economic backgrounds within each ethnic group, and I don’t have the hard data. I believe it is sufficient to say that most of our students from wealthier families are white and many of our students of color come from families and neighborhoods that most would consider lower-income. There are always exceptions to these generalizations. I also acknowledge that I am only discussing white, black, and brown students, and leaving out other significant parts of our population. I also haven’t brought learning differences into this post, which would further complicate the discussion, but these should all be important parts of any discussion of equity in education. I guess that’s the difference between an informal blog post and the book I wish I had the time (and skill) to write.

Functions – Operations, Transformations, Compositions

Several years ago, I taught PreCalculus from the COMAP PreCalculus: Modeling Our World (1st edition), which was a textbook that I really appreciated. It was very focused on good applied problems, on building conceptual understanding, and on avoiding lots of drill and kill style problems so prevalent in so many textbooks. I still use some of its problems as sources in my classes, but I did find that its lack of clear structure to its units, as well as minimal specific “vocabulary/theorems/algorithms to learn/memorize” was quite unpopular with students.

One of my favorite parts of the text was that it developed the idea of functions as a set of tools for modeling data. Based on the data that you are given, you determine which tool may be your best option. This led to a natural desire to transform or combine functions to make more sophisticated models. Suddenly, we could look at a polynomial in two different ways – is it a product of linear equations, or is it a sum of power functions? Depending on the situation being modeled, maybe one approach makes more sense than the second. And what happens if we want to divide one function by another? Suddenly, we can end up with a rational function, which can drastically change our end behavior and get us talking about a limit. What if we want to sum up different sinusoidal functions to approximate graphs that we see on an oscilloscope? And voila, we are exploring Fourier series!

The great part of thinking about a toolkit of parent functions and the various compositions, operations, and transformations on those functions, is that it allows a student to generalize what happens for any function, be it a direct variation, a sine function, a log function, or other. Playing around with Desmos makes these connections so much easier to see!


Inclusiveness in Math Education (#TMC17 Theme?)

Twitter Math Camp (TMC17) is over for this year. It took two days to start this post, and over two weeks to finish it, and there is still so much to process. This was my first one, and I’m sure that some parts are always the same, but other parts are surely unique to this year. If I had to pinpoint one overarching theme for the last week, though, it wasn’t directly about math at all.

Make no mistake – I did a lot of math, and had a lot of fun learning about new problems, playing around with new ideas, and discovering new mathematicians who I hope will continue to teach me such interesting bits of mathematics. But that wasn’t the most important part of the experience. If I were to sum up the most important part of the week in one word, it would be inclusiveness.

When I first arrived in Atlanta a week ago, I got the opportunity to meet up with an old friend, Shebah. I taught with her in Oakland almost ten years ago, and she has long since moved across the country. She comes from a family of Mexican heritage, and is engaged to a man with a Puerto Rican background. As we talked about my career, and my colleagues in math education, and this whole community of Twitter teachers, she asked about the diversity of TMC. I only knew a lot of people from their profile pictures, and although I can point out some people of color, that just highlights the lack of racial or ethnic diversity. I did mention that there is a lot of gender diversity in terms of men and women, although I do not know (nor is it really my business unless a friend or colleague chooses to share with me) how many identify as trans/non-binary/genderqueer. Is there diversity of sexual orientation? My experience is that gaydar is not to be trusted, so except for people who mentioned the gender of their partner or spouse, peoples’ sexual orientation just didn’t come up. So how diverse is TMC? The only answer I can say with confidence is that it’s not diverse enough. And right away, I had the idea of inclusion in the back of my mind. Do people who are not white feel included in the Math Twitter Blog o Sphere?

Wednesday was the Desmos Pre-Conference day, a day in which I got to see some amazing new developments in store for Desmos users, including more control for scripting when writing activities, enhancements to the Desmos Geometry app, and some interesting transformations to play with.  There was a great evening activity put on by Desmos, and I went to sleep that night so excited to be in my little world of nerdy math teachers.

And then, on Thursday, July 27, Dan Meyer published a blog post, “Let’s Retire #MTBoS”. And as a result of that post, lots of people over the next several days became hurt, angry, and felt disrespected and dismissed. Again the theme of this whole episode boiled down to inclusion. Who feels included in the #MTBoS community? Who doesn’t feel included? What can be done to bridge those gaps, to make every math education professional, new or experienced, K-12 and beyond, coaches and administrators, all feel a part of this community?

Through the rest of the week, themes of inclusion and belong arose – from which teachers felt welcome in #MTBoS (whether due to its perception as cliquish, the relative youthfulness of the organization, or due to the smaller number of non cis-white members), why there was such a relatively small number of elementary school teachers or minority teachers at TMC, to how we can improve the status and inclusion of students of color and non-male/non-binary students. A whole Twitter thread (or variety of threads) on the topic of what can and should replace “boys and girls” or “ladies and gentlemen” made its way into a Storify Posting on #Equity. Some preferred the idea of using “y’all” or a variation, some liked “scholars”, “learners”, or “my little monsters”, and some defended the older teachers who used the traditional “boys and girls” because it’s hard to change. I don’t buy that argument at all – we don’t (or shouldn’t) accept when teachers from earlier generations maintain their stereotypes and outdated language.

I have memories of my great aunt, a schoolteacher, talking about some of her “colored students” with a surprised affection, like they were overachieving in her eyes because they would sometimes perform at the same level as her “regular” students. I didn’t stand up to her comments at the time, since I was probably about 15 years old, she had been retired for probably 20 years, and my mindset was that it probably didn’t matter too much what she said in the privacy of her own home. Still, I know now that it did matter. I may have silently disagreed with her, but other people who she talked to may have been swayed by her statements. I feel like I have come a long way, but sometimes wonder just how forcefully I would confront a teacher who, whether blatantly or subtly, whether intentionally or accidentally, spoke in a manner that was offensive towards a student or group of students. And then I realize that I have a very mixed record, and that I’ve let teachers slide, not saying something in the moment, because I don’t want to get into a confrontation that will take an important discussion on a tangent. I definitely swallowed my tongue on a few occasions with parents as well when they have said things that offended me greatly. My goal for the future – to take that stand, even when it may be uncomfortable, even when it may cause some unwanted ripples. To allow a message of exclusivity, whether it means excluding teachers from our professional community or excluding students from the class culture, to be voiced without objecting to it is tacitly endorsing something that can’t happen.

So, amazingly, despite all of the great mathematical discussions and ideas that came out of TMC17, which were definitely the most fun, the ideas of equity in the math education community are a far more important takeaway to me. In light of the events in Charlottesville this past weekend, this theme is more important than ever.



#MTBoS vs #iteachmath Debate

Wow – what an amazing experience #TMC17 was. Including the Desmos pre-conference, it was 4.5 days of cultivating relationships, strengthening friendships, learning from peers, sharing my own experiences, socializing during meals and games, and soaking in a positive experience. And yet…a debate broke out on twitter that was marked by very strong feelings from two different camps. The short story is that Dan Meyer suggested (through tweets and a blog post) that it is time to retire the #MTBoS name and start using the hashtag #iteachmath instead. The response from many in #MTBoS was swift and unrelenting. And some of us mostly stayed on the sidelines, trying to process just what #MTBoS means to us.

I don’t have any answers yet, but I do have some thoughts. First, one thing that I think may have gotten lost is that both sides are really coming at this from a positive place. Maybe it’s naïve of me to believe that, but it’s also important to me that I believe that. It’s not just that I hate conflict (though that’s true), but more that I need to believe that as educators, we are people who care about our kids and our craft.

The #MTBoS does not have any membership application or member fees or anything official. It is (as Peg Cagle said this morning at breakfast) an organization where one joins by participating. Participating could be through writing blogs, through tweeting, through reading blogs, or even by lurking on Twitter.  People who were otherwise introverted and reluctant to reach out in real life at conferences, or who were in small or isolated schools and school districts, found a home in this virtual community. It grew and became a family, a network, a web of relationships. And as it grew, it took on a life of its own. Its members, many of whom identify as introverts, found an avenue to become leaders in math education, and found a community that they could love and call home.

At the beginning of my teaching career, oh, how I wish I had found #MTBoS, but it was several years before Twitter came along, and the only blogging I knew about was on LiveJournal, mostly by people much younger than I was who used it as a personal (but public) diary.  I taught in a small school, was one of only two math teachers at most in the high school, and lapped up the opportunities I had to attend the CMC-North conferences in Asilomar every year, and the NCTM Annual conferences when I could get the funding. But I was mostly in a bubble.  When I heard a few people talk about Twitter and math education almost ten years ago, I just wasn’t sold. I mean – what can be said in 140 characters? How could that be at all meaningful? And who has the time to read and write blogs?

In April 2015, I somehow got around to joining Twitter for real. I knew about a few people, and knew a few others, and eventually found a small group that I felt comfortable following, reading tweets, and reading their blogs. By the time NCTM 2016 came around, I had an idea of what #MTBoS was, and sort of felt like maybe I was on the verge of belonging. To a degree, it seemed like an exclusive group, not intentionally perhaps, but a group that was close and had developed great bonds with each other, and I wondered if I would really fit in.

And so that brings me back to the two sides of the debate. On one hand, there are many, many math educators who either don’t know about #MTBoS, don’t see the value in #MTBoS, or don’t feel invited to participate in #MTBoS. I know that they would of course be encouraged to “join” and would be welcomed with open arms, but they don’t know that. It has been said that #MTBoS wants to increase its diversity, especially in terms of people of color and in terms of more elementary school level teachers. These are necessary goals, and worthwhile goals, and something that we really need to figure out as a community if we want #MTBoS to best serve all students. However, I don’t think that changing the name is the answer. Are there possible issues with the name? Sure – it’s yet another piece of jargon that can make the group seem exclusive, it isn’t intuitive what it means, it gives the impression that a teacher needs to be active in Twitter or blogging in order to join. That isn’t the biggest obstacle, though. Changing the name is less important than tweaking the culture. Mind you, I don’t have the answer to how to change the culture – I just think that that’s the question that we have to be asking right now.

If the organization was starting over, maybe it would have made sense to use the #iteachmath hashtag, but the #MTBoS is a part of the identity of this group now. A decision to change something so fundamental to the group’s identity can feel very much like a betrayal, and can seem divisive to those who have developed a tie to this hashtag that is completely tied to the blogs, the tweets, and the bloggers and tweeps.

I don’t have an answer to this, but I think I may have identified (largely by listening to very wise members of #MTBoS over the last few days, especially Anna Blinstein, Sam Shah and Peg Cagle this morning over breakfast.) the two main issues that arose in this debate.

  1. How can we create an atmosphere within our community where non-members, especially elementary school math teachers and teachers of color, feel welcomed and don’t feel like outsiders?
  2. How can we reach that goal while preserving the tightly knit community and the parts of its identity that are so important to members of #MTBOS?

I don’t pretend to have the answers by any means to either of these two questions. I just want to be sure that, like in math class, we are addressing the problem that is being asked, and not solving a problem that doesn’t exist.

I would ask your thoughts in the comments, but the conversation has largely been hashed out on twitter, and I suspect it will continue for a while.

My Favorite Year End Review Activity

It’s the middle of summer, and I’m so far behind on blog posts I intended to write. All that free time in the summer seems to evaporate so quickly! It’s 2/3 of the way through July, and my first moment when I don’t have a family vacation, a daddy-daughter day, doctor’s appointments, car maintenance, work around the house, or scheduled work-related or scheduled math activities to do, so I get to share my favorite review activity. A lot of students like this too! I call it Speed Dating, and it’s fairly simple to set up. Each student is required to prepare one problem in advance. I give them the answer, but they need to work on how to solve the problem, and should make sure to ask any questions about the solution in advance if they feel unsure. If your class is large, you can break them up into smaller groups, and give each group the same set of problems. That way, too, all students working on a particular problem can come together to discuss their solutions in advance.

On the review day, each group should be set up in two circles – an inside circle and an outside circle, where each inside student is paired with an outside student. Make one larger space between two sets of desks – large enough to be able to walk through. This space will serve as the pivot point (explained later), but also makes it easier for students (and you, as the teacher) to get inside the circle. They should bring their solution with them as reference, and a place to take notes on the other solutions that they will see. I also include a small whiteboard and two different colored markers at each desk. Then, the fun starts.


I set a timer for three minutes, and the person on the inside explains their problem and solution, using the whiteboard. The person on the outside can use their own whiteboard marker to make notes or diagrams on the whiteboard if they have questions, and they can take notes on their own paper/tablet. When three minutes are up, they reverse roles, and have another three minutes for the outside student to explain their solution. After six minutes, students rotate.

All students move to the left, except for students at the pivot point, where one student in each pair wraps around, so that their partner stays on their left. Basically, you end up with a closed loop, where, given enough time, each student gets paired with every other student. During this process, each student gets to hear the solution to a wide variety of problems. In addition, every student is able to work on their explanation for their own problem, and through the extra practice, becomes a true expert in their problem, understanding it on a deeper and deeper level. Through the comments and questions they hear from their peers, they are able to focus on the trickiest parts of a problem, and refine their own solution.

When students are finished, they get time to re-write their solution and their updated solutions can be uploaded to our Google Classroom page and shared with their peers. I especially like this approach when doing a cumulative review, such as at the end of a semester in preparation for a final exam.

Dandy Candies + a Spreadsheet!

I know it’s probably an unpopular opinion, but I really love spreadsheets. The way you can set them up to adjust one value and have everything change, or manipulate a formula to adjust a fairly large (but manageable) set of data, really makes the calculations much more interesting and less tedious, and lets one start to make sense of some nice patterns. Spreadsheets are also (at least currently) still a part of the professional world, and properly writing an expression in the formula bar is a good and basic introduction to the syntax of programming languages. I don’t do it as often as I would like, but when the opportunity to incorporate a spreadsheet into a lesson presents itself as a good tool to simplify the calculations and get at the interesting math and conclusions, I jump at the chance. Chocolate Candies

Dan Meyer’s 3 act lesson, Dandy Candies, is an excellent way to explore basic surface area and volume comparisons. DandyCandies 4 PackagesBut what if we take it a step further?

In case you aren’t familiar with the premise, the lesson starts with a short video of 24 candies being packaged into various boxes, all with integer dimensions and a volume of 24 cubic candy units (where 1 candy = 1 cubic candy unit). Students then need to calculate the surface areas of the boxes and the length of ribbon required. But that’s about where the original problem ends. And this is where mine begins.

Students develop formulas for both surface area and ribbon length, and then create a spreadsheet in which they enter various dimensions for length, width, and height. They can then play around with different combinations to try to find some patterns that minimize both surface area and ribbon length. The next step, of course, is to minimize the actual cost. Students then must research (or be given) costs for cardboard and ribbon. For simplicity sake, we assume that 1 cubic candy unit is 1 cubic inch, meaning that we are looking for square inches of cardboard and inches of ribbon.

DandyCandiesThis gives another opportunity for some more formulas to find cost of cardboard for each configuration, cost of ribbon for each configuration, and their sum, the total cost of packaging for each box. I have a screenshot of one part of a student spreadsheet, to give an idea of what this (basically) looks like. We used Google Sheets, but this can be done in any other spreadsheet.

As a result of the extra spreadsheet work, along with some additional Gene-Wilder-as-Willy-Wonka-in-Willy-Wonka-The-Chocolate-Factoryresearch time, we now take about two full class periods on this assignment, but the amount of practice that students get with spreadsheets, spatial thinking, and applying a variety of skills makes this extra time well spent. Plus, I show a few clips from Charlie and the Chocolate Factory just to remind my students of the genius of Gene Wilder.

Why Debate in Math Class?

I have found my niche for this part of my career – I’m a math teacher and I love to make my students debate. Make no mistake – it takes some time to do a debate in class, it takes preparation, and it takes up a class period that could be used for instruction or assessment or a project or an exploration or a computer lab, which are the things that take place most days in most math classes around the country.

In the (no longer very new) Common Core Standards, Math Practice 3 (MP3) is one of the 8 Standards for Mathematical Practice, which are standards that cut across grade/content levels. MP3 states that students should be able to “Construct viable arguments and critique the reasoning of others.” A debate is defined by Oxford Dictionaries as “A formal discussion on a particular matter in a public meeting or legislative assembly, in which opposing arguments are put forward and which usually ends with a vote.” It is easy to see how well these can fit together. A student debate about a mathematical proposition is one in which they put forward arguments in favor of or opposition to the proposition. Through this process, they are given opportunities to further develop and synthesize ideas and create examples to support their arguments, which requires them to apply ideas that they can understand (and remember). In sum, it covers all the bands of Bloom’s taxonomy (which has its own controversy, acknowledged, but that’s another conversation).


For these reasons, I have found a debate to be an excellent way to review a unit after it has finished. For example, after covering solutions of linear equations in my Algebra 1 classes, we had a debate in which students argued that either elimination or substitution was the best approach to take in order to solve a linear system. I did not create an experiment that is worthy of peer review, but as a case study, in my two classes, assessment scores increased on average from 2.4 on substitution and 2.1 on elimination to 3.6 on substitution and 3.4 on elimination. The pass rates for substitution increased from 67% to 95%, and on elimination increased from 38% to 90%. (My assessments are SBG assessments scored on a scale from 0 to 4. These results cannot only explained by the debate, as students also got the feedback from their first assessments, and not all students retook their assessments. But it is some nice anecdotal evidence.)

That should be enough of a reason to include debates in math classes, but I’ve skipped over the most important reason. It’s a lot of fun! Students get to collaborate, research, and then they are encouraged to argue, with some extra points (not extra credit of course) on the line. WODBCirclesBlankThere are a variety of formats that we can use for debates, and they can range from a short “Which One Doesn’t Belong” warm up activity to a formal debate, and everything in between. Students are able to understand the protocols fairly quickly, and get used to preparing for debates because they could come up at any time. In fact they will sometimes ask if we can debate a topic if it isn’t immediately settled in class. (Case in point- a student asked if parallelograms could be defined as a subset of trapezoids. In other words, are trapezoids defined as having at least one pair of parallel sides, or exactly one pair of parallel sides? I realized that I didn’t have a definite answer, and that it isn’t a settled definition, and lo and behold, students begged for a debate, which we did a week later.)

Why Debate NCTM2017

Are you sold on debates yet? For more information, you can take a look at my Google Slides document from my presentation at the NCTM 2017 Annual Conference in San Antonio.

Math Forum Debate at NCTM 2017

This year, I was fortunate to have my first proposal to speak at the NCTM Annual Conference accepted. Even more exciting, I was invited by the Math Forum to do a presentation on debates, which then turned into an actual debate. Two friends of mine from #MTBoS, Anna Blinstein (@borschtwithanna) and Mishaal Surti (@MrSurti), agreed to have a semi-formal debate, which went over very well (despite the small audience). It’s been a week now, so it seems like a good time to reflect on this experience.

For the Math Forum debate, I have a vision of it growing into an annual math-ed celebrity debate event. Where did I get that idea? It probably goes back several years, and originated with Professor Colin Adams (whose website was last updated in 2008, but looks the same as it did during my senior year in college in 1995). I saw him more than 20 years ago at an MAA conference, in a performance as his alter-ego  Mel Slugbate, in a talk about how to cheat your way to the knot merit badge. Always creative, he wrote an excellent book on knot theory, and later debated his colleague, Thomas Garrity, on the topics of “Pi vs. e” and “Integral vs. Derivative”. (On a side note, he received his Ph.D. in math from University of Wisconsin at Madison, where mathematician, author, and NCTM 2017 opening keynote speaker Jordan Ellenberg currently teaches.)  I’m sure that hearing about and then seeing videos of those debates first put the idea of debates in math class in my mind. It’s definitely what I’d love to see annually if I can find a way to do it. There are numerous topics that can be debated in the areas of math and math education. Once I put the word out and reached out to a few people, both Anna and Mishaal graciously accepted the challenge. And now we had to decide on a topic, as well as the format.

The format was easy – I suggested some guidelines for a semi-formal debate (opening statements, closing statements, and how questions would be answered). Both Anna and Mishaal were agreeable, and that was that. The topic of debate was not too difficult of a decision; I suggested a few topics in math, and a few topics in math education, and both Mishaal and Anna were pretty excited to debate the topic of traditional sequencing of secondary math courses (Algebra 1, Geometry, Algebra 2) vs. an integrated math curriculum (which is used, basically, everywhere else in the world). And here was the problem that ended up not being a problem: both Anna and Mishaal are fans of integrated math, and so one would have to debate a side that they opposed. In the world of debate, of course, this isn’t uncommon. (I often tell the story of how I was required to take the side of allowing teenage tobacco use for a high school debate. I won the debate, making the argument that teenage smoking should be required. Not my proudest moment…or was it?)


All three of us were quite busy with, you know, all the things that come up in the lives of teachers, so our plans for great preparation were not completely fulfilled. I did create a document of research sources, and a slide show (with very few graphics), and my own list of questions for each side. Anna and Mishaal downplayed how much they prepared, but their performances during the debate were outstanding – arguments and rebuttals were well thought out, they listened to each other and responded with eloquence and intention, and they both injected humor at appropriate times.

If you’d like to see the video, it’s on YouTube (complete with quickly added end credits, Creative Commons licensed music, and minimal editing).

One thing that I’ve noticed is that, as moderator and presentation operator, I personally find it difficult to pay as close attention and take notes during the debate as I would like. As a result, I general take video of all of the debates in my classes so I can watch them afterwards. It’s also really great to have some evidence of some of the very insightful and funny things that students say.

I’ll post again with a summary of my debate talk, but right now I want to put this dream out there. Would you like to see a debate at a future math conference? Maybe a celebrity that also happens to be a mathematician debate? (I was thinking maybe Danika McKellar vs. John Urschel would be a fun one to do). What about author mathematicians? (Simon Singh vs. Keith Devlin, perhaps?) Or maybe it would be more meaningful with celebrities of #MTBoS. Perhaps…even you? Tell Suzanne and Annie and Max at Math Forum that you know you missed a great show and would like to see a debate next year! Tell NCTM you want this to happen. And tell me if you want to take part. I could always use a debater, a researcher, another camera operator or two, a video editor, a stage manager, and someone to do something about my hair and wardrobe. Say…anyone want to write a grant to fund all this?